Conventionally, a drain valve device has been known that is provided in a tank that stores wash water that washes a toilet. Such a drain valve device is such that a valve body that plugs a drain outlet arranged on a bottom surface of the above-mentioned tank is lifted, for example, according to an operation of an operation lever, and thereby, wash water is supplied to a toilet.
A drain valve device may be such that an operation lever is coupled with a valve body by an operation wire and the valve body is lifted according to a rotating operation of the operation lever (see, for example, Japanese Laid-Open Patent Publication No. 2013-100668).
However, in the above-mentioned conventional technique, a valve body remains lifted in a case where an operation time period for an operation lever is long, for example, the operation lever is rotated and held. In such a case, an amount of wash water that is supplied to a toilet is larger than that in a case where an operation time period is short, and hence, there is room for improvement from the viewpoint of water saving.